# Describe what alpha radiation is and explain why it is not considered a hazard when a radioactive source emitting only alpha radiation is kept several centimetres away from the body in open air.

> Eduqas GCSE Physics — 9.2 Absorption and emission of ionising radiations · Describe and Explain · 4 marks

## Mark scheme (4 marks)

1. Alpha radiation consists of two protons and two neutrons (a helium nucleus)
2. Alpha radiation has a very short range in air (a few centimetres)
3. Alpha radiation is stopped before it reaches the body / does not penetrate to the skin
4. Alpha radiation is highly ionising so if it did reach body tissue it would be very dangerous / hazardous internally

## Key terms

- [alpha radiation](https://www.gradenine.co.uk/glossary/alpha-radiation)
- [radioactive source](https://www.gradenine.co.uk/glossary/radioactive-source)

## Related

- [Revision notes for Eduqas GCSE Physics](https://www.gradenine.co.uk/learn)
- [How to answer "Describe and Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

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Source: [GradeNine](https://www.gradenine.co.uk/q/describe-what-alpha-radiation-is-and-bc3b192c) · Published by Druglandscape Ltd.